An oil sheen is seen as oil oozes from the marsh platform along the shoreline of Bay Jimmy, which was heavily impacted by the Deepwater Horizon oil spill, in Plaquemines Parish, La., Friday.

NEW ORLEANS — An employee of the company that owned the doomed Deepwater Horizon drilling rig testified Tuesday that he was surprised when BP scrapped his team’s design to stop the gusher in the Gulf of Mexico.

Robert Turlak, a Transocean Ltd. manager, was a witness for his employer at a federal trial that is focusing on BP’s response to the April 2010 well blowout. BP’s trial adversaries argue the company could have sealed the blown-out well much sooner if it had employed a capping strategy that Turlak and others had devised. It was ready for installation in early June.

BP ultimately used a capping stack to stop the spill July 15 after several other methods failed.

Turlak said he never heard why BP scrapped his team’s design.

“We were so close. We had come a long way,” said Turlak, Transocean’s manager of subsea engineering and well control systems.

During the first few weeks after the spill, engineers focused on two methods for stopping the flow of oil: Capping the well was one option. The other, called “top kill,” involved pumping drilling mud and other material into the Deepwater Horizon rig’s blowout preventer.

Turlak’s team was working on a strategy that was called “BOP-on-BOP” because it lowered a second blowout preventer on top of the rig’s failed one.

Turlak called it the “obvious solution,” but BP said it wasn’t a viable option because it could have made the situation worse and hampered other strategies if it failed. BP said the capping stack that later sealed the well was specifically designed to land on the well system above the blowout preventer.

BP employed the “top kill” method in May 2010, but it didn’t stop the flow of oil. Plaintiffs’ lawyers claim BP knew the strategy was doomed based on higher flow rate estimates that the company didn’t share with federal officials at the time.

The trial’s second phase opened Monday with claims that BP ignored decades of warnings about the risks of a deep-water blowout and withheld crucial information about the size of the spill.

During opening statements, BP attorney Mike Brock said the company’s efforts to stop the flow of oil were guided by an overriding principle: “Don’t make it worse.” Turlak said that was a “reasonable philosophy.”

The trial’s first phase, which ended in April, focused on the complex chain of mistakes and failures that caused the blowout.

The second phase is divided into two segments: The first centers on BP’s efforts to cap the well. The second is designed to help Barbier determine how much oil spilled into the Gulf.

The government’s estimate is some 70 million gallons more than what BP says spilled. Establishing how much oil leaked into the Gulf will help figure out the penalties the oil company must pay. Billions of dollars are at stake.

Eleven workers died in the explosion on the rig that was triggered by the blowout.